TUKTOYAKTUK
An earthquake that struck off the coast of Tuktoyaktuk last week would have shaken buildings and caused minor damage if it had happened on land, says an earthquake expert.

A 4.9 magnitude earthquake struck about 240 kilometres northwest of Tuktoyaktuk on March 23. This map shows the earthquakes that have taken place in Alaska, Yukon and Northwest Territories over the past month. - photo courtesy of Natural Resources Canada

“A 4.9 is a fairly large earthquake,” said John Cassidy, a seismologist with the federal Department of Natural Resources. “It’s one that, in a populated area, it would be significant shaking, it would frighten people if you were very close to it.”

The earthquake happened on March 23, about 240 km northwest of Tuktoyaktuk in the Beaufort Sea, Cassidy said.

It was far enough away that no one felt the quake in the community, said Mayor Darrel Nasogaluak.

Cassidy said earthquakes are common in the area.

“It is an area where we have seen earthquakes over the years so it’s not unheard of to see earthquakes beneath the Beaufort Sea,” he said.

Over the past 25 years, there have been about 75 earthquakes within 100 km of last week’s quake, Cassidy said. All were between magnitude 2 and 4.9.

Cassidy said the Yukon and western part of the NWT has a lot of seismic activity – and earthquakes.

“We see a lot of earthquakes occurring through the Richardson Mountains, the Mackenzie Mountains and we’ve seen very large earthquakes up in the magnitude 7 range, for example, through those areas,” he said. “We also have a cluster of earthquakes below the Beaufort Sea. So it is an area where we see earthquakes.”

He said the largest recorded in the Beaufort Sea, a magnitude 6.5, happened in 1920.

A magnitude 5 struck in 1975.

“Since then we’ve seen 3s and 4s,” Cassidy said.

Cassidy said even coastal regions in the North should be aware of the possibility of tsunamis as the result of a severe earthquake.

“Anywhere where large earthquakes can occur, you have the potential for tsunamis,” he said. “Generally, large tsunamis are caused by very large earthquakes underneath the ocean.”

He said while the majority of quakes have been relatively small in recent decades, there is the possibility of a strong earthquake happening in the region.

“There have been large earthquakes here,” he said. “We might expect to see large earthquakes in the future.”